NotesAI/app/src/main/java/com/example/notesai/util/FileParser.kt

package com.example.notesai.util

import android.content.Context
import android.net.Uri
import android.util.Log
import com.tom_roush.pdfbox.android.PDFBoxResourceLoader
import com.tom_roush.pdfbox.pdmodel.PDDocument
import com.tom_roush.pdfbox.text.PDFTextStripper
import java.io.BufferedReader
import java.io.InputStreamReader

object FileParser {

    private const val TAG = "FileParser"

    /**
     * Initialize PDFBox (call this in Application.onCreate or before first use)
     */
    fun initPDFBox(context: Context) {
        try {
            PDFBoxResourceLoader.init(context)
            Log.d(TAG, "PDFBox initialized successfully")
        } catch (e: Exception) {
            Log.e(TAG, "Failed to initialize PDFBox", e)
        }
    }

    /**
     * Parse file berdasarkan tipe
     */
    suspend fun parseFile(context: Context, uri: Uri): FileParseResult {
        return try {
            val mimeType = context.contentResolver.getType(uri)
            val fileName = getFileName(context, uri)

            Log.d(TAG, "Parsing file: $fileName, type: $mimeType")

            val content = when {
                mimeType == "application/pdf" || fileName.endsWith(".pdf", ignoreCase = true) -> {
                    parsePDF(context, uri)
                }
                mimeType == "text/plain" || fileName.endsWith(".txt", ignoreCase = true) -> {
                    parseTXT(context, uri)
                }
                mimeType == "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
                        || fileName.endsWith(".docx", ignoreCase = true) -> {
                    parseDOCX(context, uri)
                }
                else -> {
                    return FileParseResult.Error("Format file tidak didukung: $mimeType")
                }
            }

            if (content.isBlank()) {
                FileParseResult.Error("File kosong atau tidak dapat dibaca")
            } else {
                FileParseResult.Success(
                    content = content,
                    fileName = fileName,
                    fileType = getFileType(fileName),
                    wordCount = content.split(Regex("\\s+")).size
                )
            }
        } catch (e: Exception) {
            Log.e(TAG, "Error parsing file", e)
            FileParseResult.Error("Gagal membaca file: ${e.message}")
        }
    }

    /**
     * Parse PDF file
     */
    private fun parsePDF(context: Context, uri: Uri): String {
        val inputStream = context.contentResolver.openInputStream(uri)
            ?: throw Exception("Cannot open file")

        return inputStream.use { stream ->
            val document = PDDocument.load(stream)
            val stripper = PDFTextStripper()
            val text = stripper.getText(document)
            document.close()
            text.trim()
        }
    }

    /**
     * Parse TXT file
     */
    private fun parseTXT(context: Context, uri: Uri): String {
        val inputStream = context.contentResolver.openInputStream(uri)
            ?: throw Exception("Cannot open file")

        return inputStream.use { stream ->
            BufferedReader(InputStreamReader(stream, Charsets.UTF_8))
                .readText()
                .trim()
        }
    }

    /**
     * Parse DOCX file - SIMPLIFIED VERSION
     * Hanya extract text mentah dari XML
     */
    private fun parseDOCX(context: Context, uri: Uri): String {
        val inputStream = context.contentResolver.openInputStream(uri)
            ?: throw Exception("Cannot open file")

        return inputStream.use { stream ->
            try {
                // DOCX adalah ZIP file, kita extract document.xml
                val zipInputStream = java.util.zip.ZipInputStream(stream)
                val text = StringBuilder()

                var entry = zipInputStream.nextEntry
                while (entry != null) {
                    if (entry.name == "word/document.xml") {
                        val xmlContent = zipInputStream.bufferedReader().readText()

                        // Extract text dari XML tags
                        // Format: <w:t>text here</w:t>
                        val textPattern = Regex("<w:t[^>]*>([^<]+)</w:t>")
                        textPattern.findAll(xmlContent).forEach { match ->
                            text.append(match.groupValues[1])
                            text.append(" ")
                        }

                        // Extract text dari paragraph tags
                        val paraPattern = Regex("<w:p[^>]*>(.*?)</w:p>", RegexOption.DOT_MATCHES_ALL)
                        paraPattern.findAll(xmlContent).forEach { match ->
                            val paraContent = match.groupValues[1]
                            val textInPara = Regex("<w:t[^>]*>([^<]+)</w:t>")
                            textInPara.findAll(paraContent).forEach { textMatch ->
                                text.append(textMatch.groupValues[1])
                                text.append(" ")
                            }
                            text.append("\n")
                        }

                        break
                    }
                    entry = zipInputStream.nextEntry
                }

                zipInputStream.close()
                text.toString().trim()
            } catch (e: Exception) {
                Log.e(TAG, "Error parsing DOCX", e)
                throw Exception("Gagal membaca file DOCX: ${e.message}")
            }
        }
    }

    /**
     * Get file name from URI
     */
    private fun getFileName(context: Context, uri: Uri): String {
        var fileName = "unknown"

        context.contentResolver.query(uri, null, null, null, null)?.use { cursor ->
            val nameIndex = cursor.getColumnIndex(android.provider.OpenableColumns.DISPLAY_NAME)
            if (cursor.moveToFirst() && nameIndex != -1) {
                fileName = cursor.getString(nameIndex)
            }
        }

        return fileName
    }

    /**
     * Get file type display name
     */
    private fun getFileType(fileName: String): String {
        return when {
            fileName.endsWith(".pdf", ignoreCase = true) -> "PDF"
            fileName.endsWith(".txt", ignoreCase = true) -> "Text"
            fileName.endsWith(".docx", ignoreCase = true) -> "Word"
            else -> "Unknown"
        }
    }

    /**
     * Get file size
     */
    fun getFileSize(context: Context, uri: Uri): Long {
        var size = 0L

        context.contentResolver.query(uri, null, null, null, null)?.use { cursor ->
            val sizeIndex = cursor.getColumnIndex(android.provider.OpenableColumns.SIZE)
            if (cursor.moveToFirst() && sizeIndex != -1) {
                size = cursor.getLong(sizeIndex)
            }
        }

        return size
    }

    /**
     * Format file size untuk display
     */
    fun formatFileSize(bytes: Long): String {
        return when {
            bytes < 1024 -> "$bytes B"
            bytes < 1024 * 1024 -> "${bytes / 1024} KB"
            else -> "${bytes / (1024 * 1024)} MB"
        }
    }
}

/**
 * Result dari parsing file
 */
sealed class FileParseResult {
    data class Success(
        val content: String,
        val fileName: String,
        val fileType: String,
        val wordCount: Int
    ) : FileParseResult()

    data class Error(val message: String) : FileParseResult()
}